Airtel, a GSM service provider, offers a post-paid plan called Airtel One for its customers, with the tariff details shown below.

Mohan made an STD call, within 100 km, for 30 minutes and spent 100 minutes on local calls, split 30% on landline, 40% on GSM and 30% on Airtel. Rohan made an STD call, within 150 km, for 18 minutes and spent 120 minutes on local calls, split 30% on GSM, 40% on landline and 30% on Airtel. Who spent more on calls that month?